不进入 Onkeylistener ？无法弄清楚

Question

   package woot.wat.wen;

import android.app.Activity;
import android.os.Bundle;
import android.text.Layout;
import android.util.Log;
import android.view.KeyEvent;
import android.view.View;
import android.view.View.OnKeyListener;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.view.ViewGroup.MarginLayoutParams;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.Toast;

public class HmmActivity extends Activity implements OnKeyListener  {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        //RelativeLayout Relay=(RelativeLayout) getResources().getLayout(R.layout.main);
        ViewGroup group = (ViewGroup) findViewById(R.id.relativeLayout1);
        TextView tv=(TextView) findViewById(R.id.tv1);
        MarginLayoutParams mapara = new MarginLayoutParams(tv.getLayoutParams());
        mapara.setMargins(225, 260, 120, 120);


        LayoutParams params=new RelativeLayout.LayoutParams(mapara);
        tv.setLayoutParams(params);
        group.setFocusable(true);
        group.setOnKeyListener(this);

        int children = group.getChildCount();
        for (int i = 0; i < children; i++) {

            View child = group.getChildAt(i);
            child.setFocusable(true);
            child.setOnKeyListener(this);


            }



        //tv.setOnKeyListener(this);


    }


    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        // TODO Auto-generated method stub
        if (keyCode == KeyEvent.KEYCODE_BACK &&  event.getRepeatCount() == 0) {
              //    back=true;
                    // do something on back.
            Toast.makeText(this, "Back key pressed", Toast.LENGTH_SHORT);




            System.out.println("WTF");


                    return true;
                }



        else    

            return super.onKeyDown(keyCode, event);
    }


    public boolean onKey(View v, int keyCode, KeyEvent event) {
                if (keyCode == KeyEvent.KEYCODE_BACK /*&& event.getRepeatCount() == 0*/) {
              //    back=true;
                    // do something on back.
                    Log.d("backk", "goingoin backback");






                    return true;
                }

                else
                // TODO Auto-generated method stub
                return super.onKeyDown(keyCode, event);
                //return false;
            }






    }

正如您在代码中看到的，我试图在按下后退键时执行某些操作，但按键代码似乎从未被使用。 无论是在模拟器还是设备中，每当按下后退键时，程序似乎都不会进入 onKey 方法。知道我做错了什么吗？

我已经放置了更新的代码。

好的，我已经创建了一个新的干净项目。这里的代码

package you.packag.namespac;

import android.app.Activity;
import android.os.Bundle;
import android.view.KeyEvent;
import android.widget.Toast;

public class BlActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }

@Override
public boolean onKeyDown(int keyCode, KeyEvent event){
    if(keyCode==KeyEvent.KEYCODE_BACK){
        Toast.makeText(this, "Back key pressed", Toast.LENGTH_SHORT);
        return true; //that is important
    }else 
    return super.onKeyDown(keyCode, event);
}
}

仍然是同样的问题。未显示 toast。每次按下 back 时，程序流程/控制都会转到 return true 和 return super 语句。真的不明白这是怎么回事应该会发生。真的让我发疯。一定是我做错了一些小事。请帮忙。

Answer 1

尝试

@Override
public boolean onKeyDown(int keyCode, KeyEvent event){
    if(keyCode==KeyEvent.KEYCODE_BACK){
        Toast.makeText(this, "Back key pressed", Toast.LENGTH_SHORT).show();
        return true; //that is important
    }else 
    return super.onKeyDown(keyCode, event);
}

在您的代码中执行以下操作：

1) 在 onKey 方法之前放置 @Override

2) 将 return false 更改为 return super.onKey(keyCode, event) code>

另外 - 没有必要实现 OnKeyListener

Answer 2

尝试使用 public boolean onKeyDown( int keyCode, KeyEvent event) 来代替。

Answer 3

您应该重写onKeyDown()并设置一个onKeyDownListener。不管怎样，你可以简单地重写onBackPressed()。